1. Field of the Disclosure
The disclosure relates generally to apparatus and methods for control of fluid flow from subterranean formations into a production string in a wellbore.
2. Description of the Related Art
Hydrocarbons such as oil and gas are recovered from a subterranean formation using a well or wellbore drilled into the formation. In some cases the wellbore is completed by placing a casing along the wellbore length and perforating the casing adjacent each production zone (hydrocarbon bearing zone) to extract fluids (such as oil and gas) from the associated a production zone. In other cases, the wellbore may be open hole, i.e. no casing. One or more inflow control devices are placed in the wellbore to control the flow of fluids into the wellbore. These flow control devices and production zones are generally separated by packers installed between them. Fluid from each production zone entering the wellbore is drawn into a tubular that runs to the surface. It is desirable to have a substantially even flow of fluid along the production zone. Uneven drainage may result in undesirable conditions such as invasion of a gas cone or water cone. In the instance of an oil-producing well, for example, a gas cone may cause an in-flow of gas into the wellbore that could significantly reduce oil production. In like fashion, a water cone may cause an in-flow of water into the oil production flow that reduces the amount and quality of the produced oil.
A deviated or horizontal wellbore is often drilled into a production zone to extract fluid therefrom. Several inflow control devices are placed spaced apart along such a wellbore to drain formation fluid or to inject a fluid into the formation. Formation fluid often contains a layer of oil, a layer of water below the oil and a layer of gas above the oil. For production wells, the horizontal wellbore is typically placed above the water layer. The boundary layers of oil, water and gas may not be even along the entire length of the horizontal well. Also, certain properties of the formation, such as porosity and permeability, may not be the same along the well length. Therefore, fluid between the formation and the wellbore may not flow evenly through the inflow control devices. For production wellbores, it is desirable to have a relatively even flow of the production fluid into the wellbore and also to inhibit the flow of water and gas through each inflow control device. Passive inflow control devices are commonly used to control flow into the wellbore. Such inflow control devices are set to allow a certain flow rate therethrough and then installed in the wellbore and are not designed or configured for downhole adjustments. Some times it is desirable to alter the flow rate from a particular zone. This may be because a particular zone has started producing an undesirable fluid, such as water or gas, or the inflow control device has clogged or deteriorated and the current setting is not adequate, etc. To change the flow rate through such passive inflow control devices, the production string is pulled out, which is very expensive and time consuming.
Therefore, there is a need for downhole-adjustable passive inflow control devices.